/*
 * Copyright 2002-2004 the original author or authors.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package org.springframework.rules.closure;

import org.springframework.rules.closure.Closure;
import org.springframework.rules.closure.support.AbstractClosure;

/**
 * Returns a trimmed copy of the string form of an object.
 * 
 * @author Keith Donald
 */
public class StringTrimmer extends AbstractClosure {
	private static final StringTrimmer INSTANCE = new StringTrimmer();

	/**
	 * Returns the shared StringTrimmer instance--this is possible as the
	 * default instance is immutable and stateless.
	 * 
	 * @return the shared instance
	 */
	public static Closure instance() {
		return INSTANCE;
	}

	/**
	 * Evaluate the string form of the object, returning a trimmed (no
	 * leading/trailing whitespace) copy of the string.
	 * 
	 * @return The trimmed string
	 * @see Closure#call(java.lang.Object)
	 */
	public Object call(Object argument) {
		return String.valueOf(argument).trim();
	}

	public String toString() {
		return "trim(arg)";
	}

}